Phthalocyanines have much promise as sensitizers for photodynamic therapy, PDT, in cancer treatment. Recently studies have been done by the PI's of Projects 1 and 2 on six phthalocyanine compounds with amine or quaternary ammonium functions on axial groups attached to the central metal. These studies have shown that three of the compounds have cellular uptake and photosensitizing properties that are at least as good as those of AlPcCl, and that another has promising properties. The proposed research will generate a series of new amine and quaternary ammonium phthalocyanines designed to have still better sensitizing properties. The work has four main parts. Part I. The intermediate phthalocyanines necessary for the synthesis of the desired compounds will be made. Part II. Analogues of the four promising phthalocyanines will be synthesized that have lower polarities, higher polarities, differently positioned functional groups, multiple functional groups, varying amounts of ring face openness, non-polar face groups, higher mass central elements, different oxidation potentials, and deeper red absorptions. Part III. Sets of silicon phthalocyanines that are related to the sets of photoactive phthalocyanines AlPc(SO3H)nCl and ZnPc((CH2)3N(C2H5)2)4 will also be made. In addition, a bisammine diamagnetic transition-metal phthalocyanine will be made. Part IV. The absorption spectra, fluorescence spectra, and fluorescence quantum yields of many of these sensitizers will be determined. From the data obtained, triple-quantum yields, absorption spectra, energy levels, natural lifetimes, and oxygen quenching parameters will be obtained.